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Session 42 - Molecular Clouds: Models and Observations.
Display session, Tuesday, June 11
Great Hall,

[42.05] CS (2-1) and near--infrared mapping of the Maddalena Thaddeus Cloud

S. T. Megeath (MIT Haystack Observatory), T. L. Wilson (MPIfR)

The Maddalena Thaddeus (MT) cloud is a relatively nearby (2.2 kpc), outer galaxy molecular cloud which exhibits no evidence for recent OB star formation. MT proposed that it is a rare example of a young GMC before the onset of massive star formation. Using the SEST telescope, we mapped the central region of peak ^12CO temperatures. We detected emission from 3 clumps which were previously detected in ^13CO mapping by Williams et al. (1994 ApJ 428, 693). The CS emission of the clumps is less extended and shows much more substructure than the ^13CO emission. We compare the relative masses, densities derived from the ^13CO and CS data and present a linewidth vs. source size relationship. Near--infrared images taken from Calar Alto of one of the clumps show no evidence for stellar density enhancements or nebulosity - features commonly found towards active star forming regions. Finally, we present a pictorial comparison of K--band, IRAS, and CS maps from a number of regions to compare the MT cloud to other "well studied" molecular clouds.

Program listing for Tuesday